==> \(\frac{{21.2 \times {{10}^{ - 11}}}}{{5.3 \times {{10}^{ - 11}}}} = {\left( {\frac{n}{1}} \right)^2}\) ==> \({n^2} = 4\) ==> \(n = 2\)
[Rhc=13.6 eV, $\mathrm{hc}=1242 \mathrm{eV} \mathrm{nm}, \mathrm{h}=6.6 \times 10^{-34} \mathrm{J-s}$ અને હાઈડ્રોજન પરમાણુનું દળ $\sim 1.6 \times 10^{-27} \mathrm{~kg}$ લો.]